DE102007021693A1 - Auxiliary system for determining position of fork-lift truck in parking space, has unit for coupling and/or fixing position of vehicle, where determined position is corrected by relative positioning of vehicle relative to object - Google Patents

Abstract

The system has a unit for coupling and/or fixing a position of a vehicle (1). The vehicle includes a set of onboard sensors (2) i.e. rotary laser scanner, detecting objects (6) e.g. bottle, in surroundings, which are changeable in a position. Detected objects are compared with objects, which are inserted into an actual electronically available card. The card is updated by a position management system, The position determined by coupling and/or fixing is tested, determined and corrected reliably or exactly by the relative positioning of the vehicle relative to the object.

Description

The The invention relates to an arrangement according to the preamble of the claim 1.

Such an arrangement is from the DE 35 38 908 A1 known. In this case, the system is used to guide robots and driverless forklifts. In the case of non-rail industrial trucks, automatic guidance along induction loops or lines on the road can be provided. Furthermore, such vehicles are also led to laser marks on the walls or in the outdoor area to GPS. These guides require a considerable amount of material and installation. There are often situations where the laser marks are delivered by objects or that buildings, cranes or stacked containers do not provide adequate GPS reception. In this case, it is also possible to travel certain sections of the route by coupling the position with the aid of odometry sensors and with electronic gyros. After longer sections, however, larger and larger errors build up, so that the orientation is no longer sufficient. It is now appropriate that the robotic or driverless material handling vehicle is equipped with a board-autonomous positioning system which uses distance sensors to determine the distance of the vehicle to the technical and natural characteristics of the lateral boundary of the roadway. Each position within the operating area is characterized by a characteristic combination of the location-dependent lane width or length. The associated data are stored in an electronic map. The technical or artificial or natural features are building features, ie permanent facilities.

In In practice, however, it is a disadvantage that one on these building characteristics instructed. Especially with large storage areas These areas are sometimes relatively high, transportable units delivered. Then the view to the building features is no more given and thus no further orientation possible.

Of the The invention defined in claim 1 is based on the object to show an auxiliary system of the type mentioned, with the also then the location of the vehicle can be determined, if not Orientation to the otherwise known artificial or natural, localized features possible is. This object is achieved by the characterizing features in claim 1 solved.

The achieved with the invention benefits come into effect when For example, the permanent reference marks on the walls not are more visible or the GPS reception due to stacked too high Container is difficult or other known attitude determination method Fail by coupling and / or Bearing. Now that's going to be electronic Warehouse management system used. Here are the data or document states all pitches saved. This should be the vehicle First, an approximate indication of his Able to have. It's usually started in a known location where a bearing on known, localized features, eg. B. Laser reflectors, was possible. On another part of the way then the laser marks were not visible, so the vehicle then continued to drive by means of coupling. With increasing distance becomes However, the dead reckoning more and more inaccurate. But if that already parked objects, eg. B. Euro pallets or containers, in their Position are known, the vehicle can by capturing of the objects in the environment and by comparison with the too expected position in the map at the occupied parking spaces orientate. Thus it is possible to transport more Releasing objects relatively accurately. The determined on the way there Values by coupling with the relative position detection to the Objects compared and checked. Too big Deviations could also be given a warning signal so that further action is initiated by an operator become. As a rule, the reliability is capable been increased. The data is more accurate.

If the vehicle after discontinuation of the transported object or the coupling continues until the object is picked up again accurate and absolute orientation to fixed and artificial Trademarks may be possible through the subsequent Evaluation of continued coupling also errors of coupling more systematic or be discovered spontaneous type or calibrations are made. This also helps to improve the quality of the measurements.

The Stopping objects is, in the manner described, only relative exactly, d. H. only exactly in relation to the already parked objects. When retrieving or recording objects, this is no problem. Here, anyway, an orientation to be included in the Object necessary. For example, have the forks of a forklift drive into the designated niches in the pallets and on the container are the openings for the locking bolts to find. In this case, the auxiliary system, if it is accurate enough, d. H. So also possibly in the vicinity still works, good services prove. Otherwise, an extended system needs to know the exact location of object edges and object corners or receiving openings Find.

It is common in organized warehouses that the stock items, the storage container - in other words that Object to be transported - on known, partly also marked parking spaces, is parked. When entering or Outsourcing is addressed to any kind of warehouse management system, d. H. The document status of the parking spaces is known. The pitches are defined in a map. Thus, the vehicle can be its suspected Check the location according to the occupied parking spaces on the map.

The Be detected by on-board sensors objects in the area with the occupied parking spaces on the map matched or checked for identity. The sensors for detecting the objects may, for. B. order Radar, laser, camera, etc. act. At close range is also ultrasound possible. Sensor combinations can be general the quality, in particular the availability, and possibly also increase the accuracy.

To Claim 2, it is advantageous that the auxiliary system to support a vehicle driver serves. Possibly. it is sufficient that the driver his enter approximate starting location or its approximate Location is somehow known and a more accurate orientation determined by the environmental detection. Then, while the ride a continuous pursuit of dead reckoning be performed. While driving and / or At the destination, a more accurate orientation can be performed again so that the driver is also sure he is the right one Has reached place. Here it is usually only necessary that a parking space accuracy is achieved because the driver is in usually the picking up and setting down of the transportable objects perform yourself.

To Claim 3, it is advantageous while driving the environment to record continuously. Possibly. is located in a central location a computer with the warehouse management system. The data from the vehicle can be transmitted by radio and here with be compared to the target data of the warehouse management system.

Consequently it checks if the actual data is actually are correct. If vehicles that are not with the detection system equipped, objects taken without permission or added this can thus be determined. The listed in the map occupied or unoccupied parking spaces are then incorrect with the objects detected by on-board sensors in the environment.

The Auxiliary system is not only for driverless vehicles, but also as an assistance system for vehicles with driver or suitable for partial automation. It is for the driver in particular also advantageous if he the auxiliary system for Guidance used for his vehicle. The environmental detection can then keep him informed about how far it is still up to his goal or whether he turn right or left got to. There may also be a danger point him and he would have to reduce the speed.

If He then arrived at his destination and it is here, for example. several transportable objects, then it can the auxiliary system - after detection the environment - tell which one in this area standing objects is the searched.

To the fifth claim, it is also possible that the system is applied to superimposed objects can be. This is, for example, then advantageous if all pitches are occupied in the lower level, but the upper levels are only partial are occupied. Thus, there are again differentiation features in the upper levels.

better Accuracies are obtained according to claim 6, if the Data of environmental detection processed. Not only, but especially at standstill of the vehicle, you usually get a very large amount of data in the environment detection. The individual measured values have errors. By evaluation for plausibility, Probability, greatest agreement etc., the environment detection can be so far over move the electronic card until it fits best.

Also another vehicle is a variable in position Unit and, if its position is known, can be used for environmental detection or used for determining the position. Thus, the other vehicle not necessarily an obstacle, but almost a mobile reference.

The Embodiments of the invention are in the drawing and will be described in more detail below.

1 Vehicle with driving course and parking spaces in the top view

2 Orientation by orientation on another vehicle

3 Capture of a real object

1 shows a vehicle 1 , z. As a forklift, with an on-board sensor 2 equipped to capture the environment. At the on-board sensor 2 it can be here z. B. to act a rotating laser scanner. To Abset zen of a transported object 16 , z. As a Euro pallet with goods, drives the vehicle 1 initially on a fixed route 3 along. This driveway 3 may be dictated by a guidewire in the lane or a lane on the carriageway, transponders, magnets, GPS or other systems. At some point, the vehicle bends 1 then from the given route 3 off to the transported object 16 at the pitch 17 discontinued. Due to errors in the coupling, it believes that it is the illusion 4 drove. In fact, however, by sensing the environment by means of the sensor 2 the contours 7 a variety of parked objects 6 detected. In coordination with the data in the warehouse management computer, the true situation is now 5 of the vehicle 1 determined. The vehicle 1 is based on the contour 7 , that is, it now more accurately detects the location of the parked objects in relation to the desired parking space 17 ,

The top view shows a laser reflection mark 14 on a wall. As long as this brand of the vehicle 1 would be a determination of direction, but not an accurate determination of the vehicle 1 possible.

If no other laser reflector marks 14 visible, this alone can not be determined location. But if the contour 7 is detected, the laser reflector mark 14 be used to check or improve the location. Furthermore, the shows 1 that when the parked objects 6 higher than the laser reflection mark 14 , no visibility between vehicle 1 and the laser reflection mark 14 is possible.

In addition, it can be seen that in a vehicle 1 with driver an excellent assistant in finding a to be picked, sought after object 9 given is. If the vehicle 1 in front of several objects 6 can be adjusted by comparison with the warehouse management system and the contour 7 be determined which of the objects 6 the searched object 9 is.

A byway 13 leads the vehicle 1 to a truck parking space 12 on which is a truck 11 located. For the truck driver is the truck parking space 12 marked by colored markings on the floor. The vehicle 1 recognizes by its sensor 2 the truck contour 26 of the truck 11 , Because the position of the truck 11 always - depending on driver skills - varies, it is hereby advantageous that the vehicle 1 relative to the truck 11 can orient. The absolute position of the truck 11 is not known exactly, but the exact position of the loading space 27 on the truck 11 , The warehouse management system only has to be informed manually or automatically that the truck is being used 11 on the assigned truck parking space 12 located.

The on-board sensor 2 It may also be able to find permanent inpatient facilities, so to speak contribute to the absolute location of the situation. So you can even with a suitable design a conveyor belt 10 recognize that for the transfer of the objects to be transported 16 serves. Depending on the type of sensor 2 , z. As a distance-measuring laser scanner, it is sometimes possible obstacles 18 , which are in the guideway to recognize. These obstacles are not listed in the warehouse management computer and are therefore not for orientation.

As a sensor 2 for recording the environment or parked objects 6 , are known, depending on the given conditions, ultrasound, microwaves or optical systems. In particular, indoors, optical systems, eg. B. laser scanner because of their high detection accuracy, very well proven. In the outdoor area, however, radar sensors or even combinations between optical sensors and radar sensors can be better suited, especially in the detection of containers. In the near range, in turn, ultrasound systems are available, for finer contour detection, in particular when it is still a question of detecting the object edges and object corners. This is then possibly another benefit of the sensor 2 for exact recording of the object to be transported 16 ,

When using a laser scanner as an on-board sensor 2 must be noted that he is mounted at a suitable height, so he also the objects 6 actually recognizes. Maybe he is then so deep on the vehicle 1 mounted, that he no longer has 360 ° visibility. Even a smaller field of view may be sufficient, otherwise several on-board sensors 2 be used. Cameras and z. Even radar systems are not critical in terms of height in the assembly. If the objects 6 stacked on top of each other, multiple scanners may be required to control each level. Camera systems can u. U. control several levels simultaneously.

In 1 it is a schematic diagram with a relatively simple scenario. With restrictions, sections even a guide of the vehicle 1 only after the contours 7 , without coupling and without bearing on artificial marks possible. In most cases, however, you will find a much higher level of complexity in practice with many parking spaces at different parking spaces, so that an object detection with the on-board sensors 2 does not always lead to a clear orientation. Then it is again necessary to carry out a bearing of the situation automatically or, if necessary, manually input by a driver. The coupling is without out by a distance detection on the wheels or detection of the speed and the steering angle relatively easy to perform. The system also helps to ensure the traceability of transport orders when operating with a driver.

2 shows the orientation by bearing of a vehicle 1 under one on rails 23 guided crane 20 , z. B. a gantry crane. From the crane 20 are only the four support legs 21 or the two rail bogies shown. The vehicle has two on-board sensors 2 , With the on-board sensors 2 become the three parked objects 6 , z. B. container detected. The vehicle 1 recognizes two more of the four support legs 21 , The vehicle 1 So its position relative to the crane 20 firmly. The crane 20 has previously the three objects 6 parked and their position reported relative to its position to the warehouse management system. The current electronic map in this case consists essentially of the positions of the parked objects 6 , The vehicle 1 finds the parked objects 6 in relation to the position of the crane 20 again. The process is of course reversible, ie the vehicle 1 can the objects 6 under the crane 20 Turn off the parking position relative to the crane 20 determine and pass this position to the warehouse management system or for entry in the electronic card.

Even if you have another, scanning sensor 24 on top of the roof of the vehicle 1 would have, with all four legs 21 of the crane 20 could see directly, would be the capture of the objects 6 with the on-board sensor 2 to improve the measurement accuracy and reliability of advantage. A disadvantage of the scanning sensor 24 is that he is under the symmetrical crane 20 by itself no clear indication of direction determined. This, however, is through the on-board sensors 2 possible.

Of importance is that the positions of crane 20 or their support legs 21 as well as the positions of the objects 6 or their parking spaces are entered in the card or warehouse management system. When the objects 6 distinguish, for. B. in size or may be differently oriented, this is also noted in the warehouse management system or in the map, so that the positions are clearly recovered.

If the crane 20 gone away, can the vehicle 1 only on the parked objects 6 orientate. The accuracy of the orientation depends very much on the accuracy of the position of the parked objects 6 from.

3

A vehicle 1 that with an on-board sensor 2 , z. As a laser scanner, a parked object 6 , z. B. a crate, is detected in 3 shown in plan view. If the object 6 has an ideal, closed surface becomes the on-board sensor 2 only the contour shown here 7 see.

However, in practice, unfavorable surfaces occur with respect to detection technology. Containers z. B. trapezoidal sheets. Also difficult are crates, as they have larger recesses on the sides. When capturing the objects 6 it can happen that the measuring points 25 more or less also within the contour 7 lie. The measuring points 25 are to be prepared, for. B. by statistical averaging, suppression of the measurement points 25 within the crate, plausibility checks, etc., or combinations thereof.

By repeatedly capturing the object 6 additional measuring points result 25 Errors caused by measuring errors can be reduced as a result. The filtering of these data, that is the preparation of the measured value data, is advantageously carried out in a computer.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 3538908 A1 [0002]

Claims (7)

Auxiliary system for determining the position of a vehicle, which already has means for coupling and / or bearing the position, characterized in that - the vehicle ( 1 ) with one or more on-board sensors ( 2 ) Objects that are changeable in their position, detected in the environment, - the detected objects ( 6 ) are compared with objects that are registered in a current, electronically available map, - the objects ( 6 ) are located in known parking spaces, - the map is updated by a warehouse management system and the objects ( 6 ) are containers, containers, pallets and / or similar units which can be changed in their position and that - due to the relative position of the vehicle ( 1 ) with respect to the objects, the position determined by coupling and / or bearing is checked or more reliably or more accurately determined or corrected. Auxiliary system according to claim 1, characterized in that - a vehicle occupied by a driver ( 1 ) is checked on its route or at its current location in the situation. Auxiliary system according to one of the preceding claims, characterized in that - while driving the objects ( 6 ) is detected in the environment and it is checked whether the collected data match the object data or the occupied parking spaces in the warehouse management system. Auxiliary system according to one of the preceding claims characterized in that - it as an assistance system is used for destination guidance. Auxiliary system according to one of the preceding claims, characterized in that - a plurality of objects ( 6 ) can be stacked on top of each other and that the detection takes place in several levels. Auxiliary system according to one of the preceding claims characterized in that - for the evaluation of Environment detection data processing is used. Auxiliary system according to one of the preceding claims characterized in that - also vehicles whose Location is known to be used for environmental detection.